you must use the same rank of ips for the two pcs.
if you have 192.168.0.1 in you windows box you can assing 192.168.0.2 to you linux box. you can play with the ip number depende of you mask.
if you havea mask 255.255.255.0, you only can use 255 ips for your network, this is a class C network.
e.g.
ip: 192.168.0.1
network: 192.168.0.0
mask: 255.255.0.0
brodcast: 192.168.255.255
this will be a class B network

the hostname is the name of you box, you can use you name like bob, but you can't repeat names in other pc.
gateway is the box or router that connects you lan with internet or other network.
dns is the service that translates name address to ip address. if you need you can set up a dsn server on your linux box, or simple use the dns server of your isp.
if you are using one silgle utp cable to connect the pcs, you must use the code A in one rj, and the code B in the other.